This is an interesting usecase based on my understanding data nodes send block information to name node so if you move the block files around old data node should stop sending and new nodes would start sending. each block is a seperate file.
it would be better to try this but i dont think this is recommended for production use. inder On Nov 22, 2011 9:45 PM, "Ajit Ratnaparkhi" <ajit.ratnapar...@gmail.com> wrote: > Thanks for Help Joey! > > Does just copying block files from one drive to another work? > Isn't there metadata maintained at datanode about block locations on that > datanode? If not, then how does datanode know about blocks stored on it? > > -Ajit. > > On Tue, Nov 22, 2011 at 5:25 PM, Joey Echeverria <j...@cloudera.com>wrote: > >> The balancer only balances between datanodes. This means the new >> drives won't get used until you start writing new data to them. If you >> want to balance the drives on a node, you need to >> >> 1) copy a bunch of block files from the old drives to the new drives >> 2) shutdown the datanode >> 3) delete the old block files >> 4) configure the datanode to see the new drives >> 5) start the datanode >> >> -Joey >> >> On Tue, Nov 22, 2011 at 6:43 AM, Ajit Ratnaparkhi >> <ajit.ratnapar...@gmail.com> wrote: >> > Hi, >> > If I add additional disks to existing datanode (assume existing >> datanode has >> > 7 1TB disk which are already 80% full and then I add two new 2TB disks >> 0% >> > full) and then run balancer, does balancer balance data in a datanode? >> ie. >> > Will it move data from existing disks to newly added disks such that all >> > disks are approx equally full ? >> > thanks, >> > Ajit. >> >> >> >> -- >> Joseph Echeverria >> Cloudera, Inc. >> 443.305.9434 >> > >
